JPS6388971A - Solid-state image picking up and reproducing device - Google Patents

Abstract

PURPOSE:To compensate the defect picture element of a solid-state image pick-up element with high accuracy by perceiving the correlation between images held inherently by a video signal and calculating the compensating value of the video signal of the detect picture element from the video signal value of a limited number of picture elements at the periphery of a defect image. CONSTITUTION:A solid-state image pick-up element 2 and a ROM 4 to record the position of a defect picture element are driven by the pulse to occur from a driving pulse generating circuit 1, and the video signal of a normal element 2 is recorded through a sample/hold circuit 3, a memory 10 for a video signal and a selecting logic 9 at a video signal recording and reproducing part 6. On the other hand, the video signal of a defect element 2 controls 5 the selecting logic 9, an arithmetic circuit part 8 outputs a compensating signal value obtained by a linear coefficient to a video signal recording and reproducing part 6 as the video signal value of the defect picture element and the compensation of the defect element is executed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a solid-state imaging/playback device used for electronic still cameras, image files, etc., and particularly to a solid-state imaging/playback device with an improved defect compensation method.

[Conventional technology]

Conventionally, the yield of solid-state imaging devices used in this type of solid-state imaging and playback devices has decreased significantly due to pixel defects such as white scratches and black scratches that occur during the manufacturing process, and the cost of the devices themselves has increased. It was the cause. For this reason, defect compensation was provided to prevent high prices.

A block diagram of a conventional solid-state imaging/playback device is shown in FIG. In FIG. 5, the solid-state image sensor 2 and the ROM 4 that records the positions of defective pixels are driven by pulses generated from the drive pulse generation circuit 1, and the video signals of normal pixels of the solid-state image sensor 2 are transferred to the sample-hold circuit. 3 and recorded in a video signal recording/reproducing section 6 driven by a drive circuit section 7.

Here, when a video signal of a defective pixel is output from the solid-state image sensor 2, a timing pulse is transmitted from the ROM 4, which records the position of the defective pixel being driven, to the control circuit section 5 using the same drive pulse. , the control circuit unit 5 controls the sample and hold circuit 3 so as not to generate a sampling pulse, samples the video signal of the pixel one sample before the defective pixel twice, and outputs it as a video signal of the defective pixel. The video signal of the pixel was compensated and recorded in the video recording/reproducing section 6.

[Problem that the invention seeks to solve]

However, the conventional solid-state imaging/playback device as described above simply uses the video signal of the pixel one sample before as the video signal of the defective pixel, so the video signal of the defective pixel is 100% the pixel one sample before. However, if a defective pixel is located at the boundary of a subject image where the video signal value changes rapidly, it is necessary to compensate for the video signal value that is far from the actual video signal value. Therefore, it was insufficient to be used as a solid-state imaging/playback device for electronic still cameras, image files, etc.

In contrast to the conventional solid-state imaging/playback device described above, the present invention focuses on the correlation between images that video signals inherently have, and configures an arithmetic circuit section to detect defective pixels of solid-state imaging devices with higher accuracy. compensation can be provided.

[Means for solving problems]

The solid-state imaging/playback device of the present invention includes a solid-state imaging device, a ROM that records the position of a defective pixel of the solid-state imaging device, a sample-hold circuit that samples and holds the output of the solid-state imaging device, and a sample-and-hold circuit that samples and holds the output of the solid-state imaging device. a memory that temporarily stores the output; an arithmetic circuit unit that calculates a compensation value for the video signal of the defective pixel from video signal values of a finite number of pixels around the defective pixel; and recording and reproducing means for recording and reproducing the output signal of the arithmetic circuit section when outputted, and recording and reproducing the output signal when a normal pixel video signal is outputted from the memory. Features.

The solid-state image sensor and reproducing device of the present invention includes a solid-state image sensor, a ROM that records the position of a defective pixel of the solid-state image sensor,
a sample-and-hold circuit that samples and holds the output of the solid-state image sensor; a recording and reproducing section that records and reproduces the output of the sample-and-hold circuit; and a video signal value of a finite number of pixels around the defective pixel. an arithmetic circuit unit that calculates a compensation value of a signal; an arithmetic circuit unit that outputs an output signal of the arithmetic circuit unit when the video signal of the defective pixel is reproduced from the recording and reproducing unit; and a video signal of the normal pixel that is output from the recording and reproducing unit; The apparatus is characterized in that it includes a selection means for outputting an output signal when the reproduction is performed.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

1st. FIG. 2 is a block diagram showing an embodiment of the present invention. Generally, although a video signal is a non-stationary signal, there is a strong correlation between each pixel, and assuming stationary ergodicity, the video signal value of a certain pixel is the video signal value of several surrounding pixels. It can be expressed as a linear combination.

Let X be a data vector of N (=mn)-order video signal values as shown in FIG. Here, the true video signal value of the defective pixel is Xl, the error from the compensation value is y5, and the linear coefficient is e.
If it is Ik (however, i-2,...,N), and rewriting this in matrix form, Y=LX...(2)
(However, L is a unit lower triangular matrix.) On the other hand, the covariance matrices of Y and X are CY,
Assuming CX, equation (2) is CY = LCx L”...(3
)Cx = L-'CY (L")-'
...(4), and by performing Cholesky decomposition on the covariance matrix of the data vector X, the (N-1)th order linear coefficient is obtained. For example, the seventh row of the unit lower triangular matrix obtained from the covariance matrix of data vector X as shown in Figure 4(a) is the 6th order linear coefficient, and The fifth row of the unit lower triangular matrix obtained from the covariance matrix becomes the fourth-order linear coefficient.

Referring to FIG. 1, the first embodiment of the present invention includes a solid-state image sensor 2, its driving pulse generation circuit 1, a sample hold circuit 3, a ROM 4 that records the position of a defective pixel,
It is composed of a control circuit section 5, a video signal recording and reproducing section 6, a driving circuit 7 thereof, an arithmetic circuit section 8, a selection logic 9, and a video signal memory 10.

A ROM 4 in which the positions of the solid-state image sensor 2 and defective pixels are recorded is driven by pulses generated from a drive pulse generation circuit 1, and video signals of normal pixels of the solid-state image sensor 2 are sent to a sample hold circuit 3 and a video signal memory 10. The signal is then recorded via the select logic 9 by the video signal recording/reproducing section 6 driven by the drive circuit section 7 .

On the other hand, when a video signal of a defective pixel of the solid-state image sensor 2 is output, a timing pulse is transmitted from the ROM 4, which records the position of the defective pixel driven by the same drive pulse, to the control circuit section 5. The control circuit section 5 controls the selection logic 9, and uses the compensation signal value X+=X+'/+ obtained by the linear coefficient obtained by the above calculation from the arithmetic circuit section 8 as the video signal value of the defective pixel in the video signal recording/reproducing section. 6
Compensation for defective pixels can be performed by outputting to. Here, the dimension of the linear coefficient can be arbitrarily selected depending on the properties of the target image.

Referring now to FIG. 2, a second embodiment of the present invention is basically similar to the first embodiment of the present invention. The video output from the solid-state image sensor 2 driven by the drive pulse generation circuit 1 is once recorded in the video signal recording/reproducing section 6 via the sample hold circuit 3. Next, when the video signal is reproduced by the video signal recording/reproducing section 6 and the video signal of the defective pixel of the solid-state image sensor 2 is reproduced, the video signal recording/reproducing section 6 reproduces the video signal.
Timing pulses are sent from the ROM 4, which records the position of the defective pixel driven by the same drive circuit 7 as the reproduction section 6, to the control circuit section 5, and the control circuit section 5 controls the selection logic 9, and the arithmetic circuit. The defective pixel can be compensated for by reproducing and outputting the compensation signal value Xl obtained from the section 8 in the same manner as in the first embodiment as a video signal of the defective pixel. Again, the dimension of the linear coefficients can be arbitrarily encountered depending on the nature of the image of interest.

〔Effect of the invention〕

As explained above, the present invention focuses on the correlation between pixels that a video signal inherently has, and by configuring an arithmetic circuit section, the video signal values of a finite number of pixels around a defective pixel are This makes it possible to compensate for defective pixels in solid-state image sensors with higher accuracy even when the defective pixels are located at the boundary of the subject image, where the video signal value changes rapidly compared to the conventional method. When used as a solid-state imaging/playback device such as a file system, it has the effect of providing a more stable system than conventional systems.

[Brief explanation of the drawing]

1 and 2 are block diagrams showing an embodiment of the present invention, FIG. 3 is an explanatory diagram showing a general method of generating data vectors for calculating linear coefficients, and FIG. An explanatory diagram showing a general example of a pixel arrangement used for compensation of a video signal, and FIG. 5 is a block diagram showing a conventional example. 1... Drive pulse generation circuit, 2... Solid-state image sensor,
3... Sample hold circuit, 4... ROM that records the position of the defective pixel, 5... Control circuit section, 6... Video signal recording/reproducing section, 7... Drive circuit section, 8. ...Arithmetic circuit section, 9...Select logic, 10...Memory for video signal. If 72 73 2'4
It 72 2'300■
○■ z5 χ6 Z'7 ． 74 7! ((A)
(b) 1,400 figures

Claims (2)

[Claims] (1) A solid-state image sensor, a ROM that records the position of a defective pixel of the solid-state image sensor, a sample-and-hold circuit that samples and holds the output of the solid-state image sensor, and a memory that temporarily stores the output of this sample-and-hold circuit. , an arithmetic circuit unit that calculates a compensation value for the video signal of the defective pixel from video signal values of a finite number of pixels around the defective pixel, and the arithmetic circuit when the video signal of the defective pixel is output from the memory. solid-state imaging and reproduction, characterized in that it is equipped with a recording and reproducing means for recording and reproducing the output signal of the unit, and recording and reproducing the output signal when a normal pixel video signal is output from the memory. Device. (2) A solid-state image sensor, a ROM that records the position of a defective pixel of the solid-state image sensor, a sample-and-hold circuit that samples and holds the output of the solid-state image sensor, and a record/playback that records and plays the output of this sample-and-hold circuit. Department and
an arithmetic circuit section that calculates a compensation value for the video signal of the defective pixel from video signal values of a finite number of pixels around the defective pixel; 1. A solid-state imaging/reproduction device, comprising: a selection means for outputting an output signal of a circuit section, and outputting the output signal when a normal pixel video signal is reproduced from the recording/reproduction section.